Fire-resistant lubricating emulsion



United States Patent No Drawing. Filed June 23, 1960, Ser. No. 38,129 8 Claims. (Cl. 252-325) This invention relates to fire-resistant lubricating emul- 810118 and, more particularly, to fire-resistant lubricating emulsions which are Water-in-oil emulsions employing a high quality petroleum lubricating oil in the oil phase. In a more specific aspect the invention relates to fire-resistant hydraulic fluids.

This application is a continuation-in-part of my copending application, Serial No. 838,416, filed September 8, 1959, now abandoned, entitled Fire-Resistant Lubricating Emulsion.

It has been found necessary to develop fire-resistant lubricants for many purposes, for example, in the hydraulic systems of aircraft and inthe hydraulic systems used to operate mining machinery. Heretofore, these fire-resistant lubricants have been confined mainly to expensive fire-resistant synthetic oils. Attempts have been made to produce fire-resistant lubricants utilizing petroleum hydrocarbon lubricating oils by forming emulsions of water in such oils. Such attempts, however, were largely unsuccessful since it was found extremely difiicult to incorporate sufiicient water into the oil to produce the desired fire resistance or when sufiicient water was incorporated into the oil the resulting emulsion was unstable, i.e. it either suffered phase separation or phase inversion wherein the water became the continuous phase and oil the dispersed phase. In either event, a completely unsatisfactory material resulted.

A fire-resistant lubricating emulsion now has been found which is highly stable and which has superior fire resistance and superior lubricating properties.

It is an object of this invention to provide a fire-resistant lubricating emulsion.

It is another object of this invention to provide a fireresistant water-imoil lubricating emulsion which has superior stability and lubricating characteristics.

Other objects of this invention will be apparent from the description and claims that follow.

In accordance with this invention, there has been found a combination of a particular emulsification agent with an ethanolamine which, when introduced into a high quality solvent refined petroleum lubricating oil, will permit the formation with water of water-in-oil emulsions over a wide range of water content. The combination of the particular emulsification agent with the ethanol-.

amine of this invention not only permits a wide range of water content in the water-in-oil emulsion produced from it, but it also provides a very stable emulsion. This stability results from the modifying action of the ethanolamine on the emulsifying action of the emulsifying agent of the invention such that there is obtained the proper balance of hydrophobic and hydrophilic properties which produce the stable water-in-oil emulsion.

The emulsifying agent suitable for thisinvention is an ester-containing reaction product produced by partially esterifying polyhydric aliphatic alcohols with an acidscontaining reaction mixture produced by the oxidation of a mixture of petroleum hydrocarbons having a mean carbon chain length falling in the range of C to C which mixture is commonly known as petrolatum or microcrystalline wax. The polyhydric alcohols range in carbon chain length from C to C representative ex amples being glycerol and sorbitol. In producing these esters it is preferable that the polyhydric alcohols used in esterifying the acids content of the oxidation reaction r 3,003,957 Patented Oct. 10, 1951 mixture be incompletely esterified, i.e. that they retain at least one unreacted hydroxyl group.

The petrolatum or rnicrocrystalline wax is subjected to liquid-phase oxidation as shown in United States Patents Numbers 1,768,523 and 1,828,356 at a temperature of about 140 C., a pressure of about 200 pounds per square inch of air and an air flow of from 250 to 300 cubic feet per minute per 2,000 gallons of wax. The oxidation is continued for approximately eight hours to produce an oxidate having an acid number of from 23 to 26, a saponification number not in excess of about 75, an ester number of from 44 to 52, and an unoxidized hydrocarbons content of from about 55 to 60 percent. It has been found that the hydrocarbon mixture maybe oxidized to the desired acid number and saponification number range in times shorter than eight hours, for example, in some instances from 6 /5. to 7 hours because of minor variations in the charge material and in the reaction conditions during the oxidation. However, generally an eight-hour oxidation time is required to produce an oxidate having the described desired specifications. The oxidate and the C -C polyhydric alcohols are reacted at a temperature of the order from 140 C. to 200 C. with the heating continued at 200 C. for about four hours. The quantity of alcohol employed is calculated so that the esterified product will have an acid number of from about 10 to 18 and a saponification number not in excess of generally'between 40 and 75. The esterified product has been found to have a flash point of the order of 400 F., and a melting point of the order of 110 F. For the sake of brevity in the description and claims the partial esters produced as has been described will be referred to as partial esters of wax acids.

The quantity of partial esters of wax acids suitable for use in preparing the fire-resistant lubricating emulsions of this invention should range from 1.0 volume percent to 10.0 volume percent and preferably from 2.0 volume percent to 5.0 volume percent based on the total volume of the oil phase of the emulsion.

The ethanolamine may be either the mono-, di-, or triethanolamine with mono-ethanolamine being preferred. The quantity of ethanolamine should range from 0.05 volume percent to 1.0 volume percent based on the total volume of the oil phase, and preferably from 0.1 to 0.5 volume percent.

It is important that the lubricating oil into which the described emulsifier and ethanolamine are blended be of high quality. The most suitable lubricating oil is a solvent refined petroleum lubricating oil having a viscosity from to 2,500 Saybolt Sections Universal at The most useful lubricating oil base; however, is one having a viscosity ranging from 100 to 300 Saybolt Seconds Universal at 100 F.

Although it is important that the lubricating oil base be of high quality, present day equipment requires that the oil contain extreme pressure and anti-wear agents. Consequently, it is preferable that the oil contain extreme pressure and anti-wear agents such as from 0.5 volume percent of 3.5 volume percent based on the total volume of the oil composition of sulfurized sperm oil and from 0.5 volume percent to 3.5 volume percent of an oil solution of lead diamyldithiocarbamate. Preferably the .volumes of sulfur-ized sperm oil and lead diamyldithiocarbamate solution should be equal although other'ratios permitted within the critical ranges of these components are completely suitable. The sulfurized sperm oil is preferably the non-corrosive reaction prod of sulfur, however, this amount is not critical. The lead diamyldithiocarbamate is sold commercially as a 50 weight percent solution in an oil having a viscosity of 100 Saybolt Seconds Universal at 100 F. The specific gravity of this commercial solution of 50 weight percent lead diamyldithiocarbamate in oil is approximately 1.095. Consequently, with the above-mentioned concentration range of from 0.5 volume percent to 3.5 volume percent of the 50 weight percent solution in oil the total oil phase of the emulsion will contain from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of the oil phase. Falex machine wear tests on the instant lubricating composition have shown that the combination of sulfurized sperm oil and lead diamyldithiocarbamate is superior in load carrying and anti-wear characteristics to either additive alone.

The quantity of lubricating oil should range from 8200 volume percent to 97.95 volume percent based on the total volume of the oil phase of the emulsion if the lead diamyldithiocarbamate is utilized in the form of the 50 weight percent solution in oil described above, which solution has a specific gravity of 1.095. If the lead diamyldithiocarbamate is not utilized in an oil solution or is utilized in an oil solution of a different concentration, then it is more convenient to express the quantity of lead diamyldithiocarbamate in terms of grams per milliliter of oil phase in the described range and the total quantity of lubricating oil will range from 85.50 volume percent to 98.45 volume percent. With the preferred ranges of the partial esters of wax acids and ethanolamine the volume of the lubricating oil should range from 87.5 volume percent to 96.9 volume percent if the lead diamyldithiocarbamate is utilized in the form of the afore-mentioned 50 weight percent solution in oil. If, however, the lead diamyldithiocarbamate is utilized in a form other than the 50 weight percent oil solution it is preferred to express its concentration as ranging from 0.0027 gram to 0.019 gram per milliliter of the oil phase and the preferred total quantity of lubricating oil will then range from 91.0 volume percent to 97.4 volume percent.

A preferred lubricating emulsion consists of from 5 percent to 95 percent by weight of water with the oil phase consisting essentially of 3.88 volume percent partial esters of wax acids, 0.12 volume percent monoethanolamine, 1.5 volume percent sulfurized sperm oil, and 94.5 volume percent solvent refined lubricating oil having a viscosity of 100 Saybolt Seconds Universal at 100 F., and having 0.0082 gram of lead diamyldithiocarbamate per milliliter of the oil phase.

In addition to the extreme pressure and anti-wear agents, it is sometimes desirable to incorporate into the base oil conventional oxidation inhibitors and rust inhibitors. For example, up to 1 gram of oxidation inhibitor per 100 milliliters of base lubricating oil may be used without disturbing the stability of the emulsions produced from the oil. It has been found that certain combinations of oxidation inhibitors are particularly desirable such as up to 0.5 gram diter-tiary butyl paracresol and up to 0.5 gram of a mixture of octylated and styrenated diphenylamine per 100 milliliters of oil. The octylated and styrenated diphenylamine is sold commercially under the name of Agerite Stalite and is an alkylation mixture produced by the reaction of di-iso butylene, styrene and diphenylamine in the presence of an aluminum chloride catalyst as disclosed in United States Patent No. 2,530,769 to Arthur T. Hollis. Preferably 0.2 gram of each of these additives per 100 milliliters of oil should be used. Good 111st inhibition is obtained without emulsion instability if up to 1.0 volume percent of a conventional rust inhibitor is employed. Smaller quantities of certain rust inhibitors can be employed advantageously, such as up to 0.1 volume percent of the reaction produce of di(2-ethylhexyl)amine with a lauryl acid phosphate mixture having a mole ratio of 2 moles of mono-lauryl acid phosphate to 1 mole of di-lauryl acid phosphate. Preferably 0.03 volume percent of this latter additive should be employed to obtain rust inhibition without harming the other properties of the emulsion produced from the lubricating oil base composition.

Water may be readily emulsified into the lubricating oil base composition containing the aforementioned partial esters of wax acids emulsifier, ethanolamine and additives. The oil and water can be emulsified with mild stirring and as the emulsion is used to lubricate gears, pumps, and similar machinery the oil and water are further emulsified to produce exceedingly stable water-in-oil emulsions. The combination of the partial esters of wax acids emulsification agent with the ethanolamine permits the formation of emulsions containing from 5 percent by weight to percent by weight of water. In general, fire resistance is proportional to the water content of the emulsion. With emulsions containing 40 percent by weight of Water or more, adequate fire resistance for hydraulic fluid applications is obtained, however, for certain other purposes water contents ranging from 5 percent to 40 percent by weight provide suflicient fire resistance. When there is from 65 percent to 95 percent by weight of water in the emulsion the fire resistance is exceedingly high but the viscosity of the emulsion is also rather high, thereby limiting the use of such emulsions. Emulsions having a water content ranging from 40 to 65 percent by weight have been found to have the greatest utility since these emulsions exhibit excellent fire resistance and have viscosities which are sufiiciently high to give excellent lubrication yet are fluid enough such that the emulsion feeds freely to gears and pumps without cavitation. These latter emulsions are particularly useful as fire-resistant hydraulic fluids.

It has been found that for best results the hydraulic fluids should have a viscosity ranging from approximately to 400 Saybolt Seconds Universal at operating temperatures which temperatures may range from 100 F. to F. and that such fluids should not have viscosities greatly in excess of 5000 Saybolt Seconds Universal at starting temperatures which may be as low as 40 F. to 50 F. It will be understood that the water phase of the emulsion of this invention may contain freezing point depressants such as methanol, ethanol, ethylene glycol and the like, when the emulsions are exposed to ambient temperatures below the freezing point of the emulsion not containing such depressants in the water phase. The emulsions of this invention containing from 40 to 65 weight percent of water have viscosities within the desired ranges set forth for hydraulic fluids and accordingly such emulsions are particularly suitable for those uses which require fire-resistant hydraulic fluids. It has been found in particular that in emulsions containing from 40 percent to 65 percent by weight of water the volume percent of the partial esters of the wax acids emulsifying agent combined with the volume percent of the ethanolamine should range from 3.0 percent to 4.5 percent based on the total volume of the oil phase of the emulsion with the ethanolamine, preferably monoethanolamine, ranging from 0.1 percent to 0.3 percent by volume based on the total volume of the oil phase and the partial esters of the wax acids emulsifying agent ranging from 2.7 volume percent to 4.4 volume percent based on the total volume of the oil phase of the emulsion. If less than the 3.0 percent by volume of the emulsifying agent and ethanolamine combination is employed the emulsion particles are too large which causes increased wear in the machine being lubricated by the emulsion and also the emulsion has a tendency to invert to an oil-in-water emulsion which causes emulsion separation and machine failure. Frequently if more than the 4.5 volume percent of the emulsifying agent and ethanolamine is employed the emulsion is too viscous and accordingly cavitation occurs and the machine wears excessively. If less than 0.10 volume percent of ethanolamine based on the total volume of the oil phase is used in the composition, the emulsion is too viscous for a satisfactory hydraulic oil, and if more than 0.3 volume percent of ethanolamine is employed, there is a tendency of the emulsion to invert to an oil-in-water emulsion. These desired quantities of partial esters of wax acids and ethanolarnine may be combined with the aforementioned quantities of sulfurized sperm oil, lead diamyldithiocarbamate and solvent refining lubricating oil.

A hydraulic fluid comprising from 40 to 65 percent by weight of water in the dispersed phase and an oil phase comprising 3.88 volume percent partial esters of wax acids, 0.12 volume percent mono-ethanolamine, 1.5 volume percent sulfurized sperm oil, and 94.5 volume percent solvent refined lubricating oil having a viscosity of 100 Saybolt Seconds Universal at 100 F., and having 0.0082. gram of lead diamyldithiocarbamate per milliliter of the oil base has been found to be exceedingly useful.

The fire-resistant emulsions of this invention are characterized by having the water droplets dispersed in the oil uniformly and of a uniformly small size. The diameter of the water droplets should range preferably between 0.001 inch and 0.0001 inch. This droplet size range produces superior emulsion stability, superior lubrication, lower evaporation tendencies, superior low temperature properties, and more uniform viscosity in service. In addition, water droplets in this size range have the ability to pass through filters without blocking or aggregating. Water droplets larger than approximately 0.001 inch in diameter give emulsions which are unstable and have inferior properties compared with those described above. When the water droplet size is smaller than approximately 0.0001 inch in diameter the viscosity of the emulsion increases rapidly with the result it is not always possible to hold the emulsion within the viscosity ranges desired based on the quantity of water contained in the emulsion. The emulsion compositions of this invention have water droplets within the desired droplet size range of from 0.001 inch to 0.0001 inch.

The following examples are provided for the purpose of illustrating certain specific embodiments of the invention and demonstrating certain critical features of the invention.

The partial esters of Wax acids employed in these examples were prepared by the partial esterification of C -C polyhydric alcohols, sorbitol predominating, of the acidscontaining reaction mixture produced by the 8-hour liquid phase oxidation of petrolatum as described herein. The partial esters of the wax acids product had an acid number of 10 and a saponification number of 54.

The ethanolamine employed in these examples was mono-ethanolamine. The sulfurized sperm oil prepared as described herein contained 10 weight percent sulfur. The lead diamyldithiocarbamate employed was in the form of the described 50 weight percent solution in oil which solution had a specific gravity of 1.095.

The solvent refined lubricating oil employed in the examples had a viscosity of 100 Saybolt Seconds Universal at 100 F. and contained 0.2 gram per 100 milliliters of oil of ditertiary butyl paracresol, 0.2 gram per 100 milliliters of oil of the decrihed octylated and styrenated diphenylamine, and 0.03 volume percent of the reaction product of di(2-ethylhexyl)amine with a lauryl acid phosphate mixture having a mole ratio of 2 moles of monolauryl acid phosphate to 1 mole of dilauryl acid phosphate.

EXAMPLE I A water-in-oil emulsion containing 55 Weight percent water was prepared in which the oil phase contained 2.7 volume percent partial esters of wax acids, 0.3 volume percent mono-ethanolamine, 1.5. volume percent sulfurized sperm oil, 1.5 volume percent lead diamyldithiocarbamate, and 94.0 volume percent solvent refined lubricating oil. This emulsion was employed to lubricate a Vickers pump at a temperature of F. and'a pressure of 1,000 pounds per square inch. The weight loss of the pump ring and vanes was measured and it was found that the wear rate was 225 milligrams per 1000 hours. The wear rate for a high quality oil containing anti-wear additives in such a test is generally of the order of 40 milligrams per 1000 hours whereas a similar oil without anti-wear additives has a wear rate of 1,300 milligrams per 1000 hours. Accordingly, it will be seen that the emulsions of this invention provide excellent lubrication under exceedingly severe operating conditions.

EXAMPLE n An emulsion containing 55 weight percent water was prepared employing an oil phase containing 3.88 volume percent partial esters of wax acids, 0.12 volume percent of mono-ethanolamine, 1.5 volume percent sulfurized sperm oil, 1.5 volume percent lead diamyldithocarbamate, and 93.0 volume percent solvent refined lubricating oil. This emulsion was tested in a Vickers pump at 1000 pounds pressure for 167 hours at 150 F. and for an additional 50 hours at F. At the end of the total of 217 hours on test the emulsion had lost approximately 4 weight percent water but was uniform and of small particle size indicating that it was still stable. The wear rate was measured and it Was found to be approximately the same or less than the wear rate found for the emulsion of Example I.

EXAMPLE III Three emulsions were prepared each containing 55 weight percent Water but having slightly different oil phase compositions with the amounts of each component expressed in volume percent of the entire oil phase as follows:

Emulsion N0. 1

Partial esters of Wax acids 3.6 Monoethanolamine 0.4 Lead diamyldithiocarbamate 3.0 Solvent refined lubricating oil 93.0

Emulsion N0. 2

Partial esters of wax acids 3.6 Monoethanolamine 0.4 Sulfurized sperm oil 3.0 Solvent refined lubricating oil 93.0

Emulsion N0. 3

Partial esters of wax acids-- 2.7 Monoethanolamine 0.3 Sulfurized sperm oil 1.5 Lead diamyldithiocarbamate 1.5 Solvent refined lubricating oil 94.0

These emulsions were tested by the Falex extreme pressure test wherein the test load was increased by 250- pound increments every 5 minutes. Emulsion No. 1 failed by seizure in 1 minute at 1,250 pounds load. Emulsion No. 2 failed by seizure in 1 minute at 1,000 pounds load. Emulsion No. 3 had not failed at a load of 3,750 pounds but the test was stopped because too much water had evaporated from the emulsion. These data demonstrate that the combination of sulfurized sperm oil and lead diamyldithiocarbamate is superior to either of such materials alone in the emulsions of this invention.

EXAMPLE IV The emulsion of Example I was tested for flammability as measured by Federal Test Method Standard No. 79 l- 352T in which a pipe cleaner is soaked in the test fluid, mounted on a windshield-wiper motor and passed back and forth through a gas flame until ignition occurs. A large number of cycles indicates a high fire resistance.

Partial esters of wax acids 1.0-10.0 Ethanolamiue 0.05-1.00 Sulfurized sperm oil 0.5-3.5

Solvent refined lubricating oil 98.45-85.50

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling within the range C C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from 80 to 2500 Saybolt Seconds Universal at 100 F., and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of oil phase.

2. A fire-resistant water-in-oil lubricating emulsion in which the water phase constitutes from 5 weight percent to 95 weight percent of the emulsion and the oil phase constitutes from 95 weight percent to 5 weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume percent based on the total volume of the oil phase:

Partial esters of wax acids Lil-10.0 Ethanolamine 0.05-1.00 Sulfurized sperm Oil O.5-3 .5 Solvent refined lubricating oil 98.45-85.50

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling Within the range C -C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from 100 to 300 Saybolt Seconds Universal at 100 F., and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of oil phase.

3. A fire-resistant Water-in-oil lubricating emulsion in which the water phase constitutes from 5 weight percent to 95 weight percent of the emulsion and the oil phase constitutes from 95 Weight per cent to 5 Weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume percent based on the total volume of the oil phase:

Partial esters of wax acids 2 5 0 Ethanolamine 0.1-0.5 Sulfurized sperm oil 0.5-3.5 Solvent refined lubricating oil 97.4-91.0

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling Within the range C -C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from to 2500 Saybolt Seconds Universal at 100 F., and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of oil phase.

4. A fire-resistant water-in-oil lubricating emulsion in which the water phase constitutes from 5 weight percent to Weight percent of the emulsion and the oil phase constitutes from 95 Weight percent to 5 weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume per cent based on the total volume of the oil phase:

Partial esters of wax acids 2.0-5.0 Ethanolamine 0.1-0.5 Sulfurized sperm oil 0.5-3.5 Solvent refined lubricating oil 97.4-91.0

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling within the range C C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from to 300 Saybolt Seconds Universal at 100 F., and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of oil phase.

5. A fire-resistant Water-in-oil lubricating emulsion in which the water phase constitutes from 5 weight percent to 95 weight percent of the emulsion and the oil phase constitutes from 95 weight percent to 5 weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume per cent based on the total volume of the oil phase:

Partial esters of wax acids 3.88 Mono-ethanolamine 0.12 Sulfurized sperm oil 1.5 Solvent refined lubricating oil 94.5

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling Within the range C C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity of 100 Saybolt Seconds Universal at 100 F., and contains 0.2 gram per 100 milliliters of oil of ditertiary butyl paracresol, 0.2 gram per 100 milliliters of oil of octylated and styrenated diphenylamine and 0.03 volume percent of the reaction product of di(2-ethylhexy1)amine with a mixture having a mole ratio of 2 moles of monolauryl acid phosphate to 1 mole of dilauryl acid phosphate, and wherein the oil phase contains 0.0082 gram of lead diamyldithiocarbamate per milliliter of oil phase.

6. A fire-resistant hydraulic fluid in the form of a Waterin-oil emulsion in which the Water phase constitutes from 40 weight percent to 65 weight percent of the emulsion and the oil phase constitutes from 60 weight percent to 35 weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume percent based on the total volume of the oil phase:

Partial esters of wax acids 1.0-10.0 Ethanolamine 0.05-1.00 Sulfurized sperm oil 0.5-3.5 Solvent refined lubricating oil 98.45-85.50

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling within the range C -C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from 80 to 2500 Saybolt Seconds Universal at 100 F., and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diamyldithiocarbamate per milliliter of oil phase.

7. A fire-resistant hydraulic fluid in the form of a water-in-oil emulsion in which the water phase constitutes from 40 weight percent to 65 weight percent of the emulsion and the oil phase constitutes from 60 weight percent to 35 weight percent of the emulsion, said oil phase consisting essentially of the following ingredients in volume percent based on the total volume of the oil phase:

Partial esters of wax acids and ethanolamine combination wherein the ethanolarnine ranges from 0.1 to 0.3 volume percent and the partial esters of wax acids range from 4.4

to 2.7 volume percent 3.0-4.5 Sulfurized sperm oil 0.5-3.5 Solvent refined lubricating oil 96.5-92.0

wherein the partial esters are the reaction product obtained by partially esterifying a polyhydric aliphatic alcohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling within the range C -C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity within the range from to 2500 Saybolt Seconds Universal at F, and wherein the oil phase contains from 0.0027 gram to 0.019 gram of lead diarnyldithiocarbamate per milliliter of oil phase.

8. A fire-resistant hydraulic fluid in the form of a waterin oil emulsion in which the water phase constitutes from 40 weight percent to 65 weight percent of the emulsion and the oil phase constitutes from 60 weight percent to 35 weight percent of the emulsion, said oil phase consisting essential of the following ingredients in volume percent based on the total volume of the oil phase:

Partial esters of wax acids 3.88 Mono-ethanolamine 0.12 Sulfurized sperm oil 1.5 Solvent refined lubricating oil 94.5

wherein the partial esters are the reaction product obtained by partially esteri'fying a polyhydric aliphatic a1- cohol having a carbon chain length of from C to C with the high molecular weight aliphatic carboxylic acids content of an oxidate of a petroleum hydrocarbon mixture having a mean carbon chain length falling within the range C C subjected to controlled liquid-phase partial oxidation for a period of the order of 8 hours said oxidate having an acid number of from about 23 to about 26 and a saponification number of not in excess of about 75, wherein the solvent refined lubricating oil has a viscosity of 100 Saybolt Seconds Universal at 100 F. and contains 0.2 gram per 100 milliliters of oil of diteritary butyl paracresol, 0.2 gram per 100 milliliters of oil of octylated and styrenated diphenylarnine and 0.03 volume percent of the reaction product of di(2-ethylhexyl)amine with a mixture having a mole ratio of 2 moles of mono-lauryl acid phosphate to 1 mole of dilauryl acid phosphate, and wherein the oil phase contains 0.0082 gram of lead diamyldithiocarbamate per milliliter of oil phase.

References Cited in the file of this patent UNITED STATES PATENTS 2,744,870 Stillebroer et al May 8, 1956 2,894,910 Francis et al July 14, 1959 2,907,714 Francis et a1 Oct. 6, 1959 FOREIGN PATENTS 207,584 Australia Apr. 23, 1957 216,326 Australia Dec. 13, 1956 

1. A FIRE-RESISTANT WATER-IN-OIL LUBRICATING EMULSION IN WHICH THE WATER PHASE CONSTITUTES FROM 5 WEIGHT PERCENT TO 95 WEIGHT PERCENT OF THE EMULSION AND THE OIL PHASE CONSTITUTES FROM 95 WEIGHT PERCENT TO 5 WEIGHT PERCENT OF THE EMULSION, SAID OIL PHASE CONSISTING ESSENTIALLY OF THE FOLLOWING INGREDIENTS IN VOLUME PERCENT BASED ON THE TOTAL VOLUME OF THE OIL PHASE: PARTIAL ESTERS OF WAS ACIDS ------------ 1.0-10.0. ETHANOLAMINE -------------------------- 0.05-1.00 SULFURIZED SPERM OIL ------------------ 0.5-3.5 SOLVENT REFINED LUBRICATING OIL ------- 98.45-85.50 WHEREIN THE PARTIAL ESTER ARE THE REACTION PRODUCT OBTAINED BY PARTIALLY ESTERIFYING A POLYHYDRIC ALIPHATIC ALCOHOL HAVING A CARBON CHAIN LENGTH OF FROM C3 TO C6 WITH THE HIGH MOLECULAR WEIGHT ALIPHATIC CARBOXYLIC ACIDS CONTENT OF AN OXIDATE OF A PETROLEUM HYDROCARBON MIXTURE HAVING A MEAN CARBON CHAIN LENGTH FALLING WITHIN THE RANGE C26-C50 SUBJECTED TO CONTROLLED LIQUID-PHASE PARTIAL OXIDATION FOR A PERIOD OF THE ORDER OF 8 HOURS SAID OXIDATE HAVING AN ACID NUMBER OF FROM ABOUT 23 TO ABOUT 26 AND A SAPONIFICATION NUMBER OF NOT IN EXCESS OF ABOUT 75, WHEREIN THE SOLVENT REFINED LUBRICATING OIL HAS A VISCOSITY WITHIN THE RANGE FROM 80 TO 2500 SAYBOLT SECONDS UNIVERSAL AT 100*F., AND WHEREIN THE OIL PHASE CONTAINS FROM 0.0027 GRAM TO 0.019 GRAM OF LEAD DIAMYLDITHIOCARBAMATE PER MILLILITER OF OIL PHASE. 